Fat embolism will always be a risk when conducting a BBL. That being said, they are very rare. Fat injection can happen two different ways; injection into the gluteus muscle and injection into the existing buttocks fat. The gluteus muscle is what contains the blood vessels your plastic surgeon will want to stay away from, and there are several techniques he will use to do so. First his grafting instrument should be tipped with a blunt end, with the hole releasing the tissue on the bottom end of the tip - the blunt edge allows the tool to move blood vessels out of the way instead of puncturing them. Secondly all tissue deposits are done superficially; which means the tissue is injected on top of the layers already there, instead of deeper inside the fat and muscle layers. Lastly, the surgeon should employ a retracting motion with his tool while injecting the tissue - keeping him clear of any blood vessels even further. I suggest finding a board certified plastic surgeon that has plentiful experience in BBL's. Consult with him or her and I'm confident you will feel at ease. They are rare. SAFETY and more SAFETY is every surgeons top concern. Best wishes.